Should I be worried if I have high TSH and T4 levels that does not exceed the reference range?
Hi, I have high TSH and high T4 levels that does not exceed the reference range. What does high TSH and T4 levels mean, and should I be worried about it? Is it necessary to check the levels yearly?
You mention having a high TSH and a Free T4 within the normal reference range. This is subclinical hypothyroidism. You don’t have to be worried about and I’ll explain more below.
The commonest cause of subclinical hypothyroidism is Hashimoto’s thyroiditis. This is when there is presence of antithyroid peroxidase antibodies. The annual rate of progression from subclinical hypothyroidism to overt hypothyroidism (this is when Free T4 level is low and TSH is high) is around 2-4%, and is higher if antithyroid perixidase antibody is positive. If you develop overt hypothyroidism, treatment with levothyroxine (oral tablet) will help normalize your thyroid function.
Most people with subclinical hypothyroidism do not experience any symptoms. If TSH level is less than 10 IU/L, treatment may not be indicated and follow up with annual blood test is recommended. If a woman of the reproductive age group is diagnosed with subclinical hypothyroidism, and she desires to get pregnant, she should be treated with Levothyroxine to optimise pregnancy outcomes.
Hope this helps!